Isn't the isometric Camera looking better? Or its just my impression? Perhaps its my nostalgy for old games?
Why the Isometric Camera is better for performance:
1- It shows less units at the time.
2- It doesnt need the zoom. So it needs less LODs, and less detail on the units.
3- It doesnt require the sky, horizon mountains etc...
4- Can make the typical dark fog of war that isometric rts's like Age of Empires 2. In perspective camera that is more challenging.
The benefits of the Perspective:
1- More realism.
2- Better zoom.
3- Better atmosphere? (Depends on the taste).
4- Better usability. Better to select more units and have a better grasp of the whole map and game.